Combined safety stop and brake means for paper-cutting machines



06E. 26, 1954 w c, RUPP 2,692,668

COMBINED SAFETY STOP AND BRAKE MEANS FOR PAPER-CUTTING MACHINES Filed Feb. 8, 1951 3 Sheets-Sheet l IN V EN TOR.

WILL/AM C RUPP BY A) We lzVEy Oct. 26, 1954 w. c upp COMBINED SAFETY STOP AND BRAKE MEANS FOR PAPER-CUTTING MACHINES 5 Sheets-Sheet 2 Filed Feb. 8, 1951 i W INVENTOR. WILL/AN C. hUPP BY A TTORIVEYS.

Oct. 26, 1954 w. c. RUPP 2,692,668

COMBINED SAFETY STOP AND BRAKE MEANS FOR PAPER-CUTTING MACHINES Filed Feb. 8, 1951 I5 Sheets-Sheet 3 INVENTOR. W/L L MM C. RUPP Patented Oct. 26, 1954 UNITED STATES EPAEENT ()FFl-CE COMBINED SAFETY STOP AND BRAKE NIEANS FOR PAPERCUTTING MA- CHINES Application February 8, 1951, Serial No. 210,000

9 Claims. .1

This invention relates as indicated to novel safety stop means for paper cutting machines, and more particularly to safety means adapted to prevent further reciprocation of the knife of a paper cutting machine in the event the brake mechanism normally automatically operative at the end of a cycle fails to. operate,

In my co-pending application Serial No. 112,659, filed August 27, 1949, new Patent No; 2,633,219, for Brake Mechanism for Paper Cutting Machines and the Like, I disclose and claim certain novel brake mechanism adapted to be adjusted automatically to stop the knife bar in its reciprocation at precisely the desired point and preventing further inadvertent operation of the machineuntil such brake, mechanism has been released by the operator. The present invention has for its primary purpose the provision of additional safety means effective positively to prevent the repetition of a cycle of the machine in the event of. failure of the brake mechanism due, for example, to improper adjustment of the latter, excessive wear, etc. It is, of course, most desirable that reciprocation of the knife be stopped in the normal manner by operation of the brake mechanism to facilitate smooth running of the machine, and to avoid the jar incurred upon imposition of positive stop means. It is accordingly afurther object of my invention so to interconnect such brake mechanism and stop means that the latter will be brought into operation. only upon failure of the brake mechanism to function as expected.

Power driven paper cutting machineshave long been employed for the purpose of cutting and trimming stacks of paper sheets, and their gen-- eral construction has become fairly well standardized. Such machines ordinarily comprise a bed or table upon which a stack of sheets may be precisely positioned by means of adjustable gauges and a vertically reciprocable knife which is drawn down and again elevated by means of a power driven crank. Since it is generally necessary for the operator manually to position the stacks of sheets to some degree on the table, it is of considerable importance that the machine should not he accidentally actuated during such preliminaries, as otherwise very serious accidents may result. It is also important that after completion of a cut the knife should return to fully elevated position and remain there. Otherwise, the operator may be endangered and also if the knife has again partially descended before being brought to rest there may not be sufiicient clearance for removal of the stack of sheets and insertion of a new stack.

In addition to the foregoing, other objects of my invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting: forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be; employed.

In said annexed drawing:

Fig. l is an elevational showing of a drive unit assembly for a paper cutting machine including my novel cycle control and automatic stop mechanism;

Fig. 2 is an enlarged fragmentary detail view of a portion of the mechanism of Fig. 1 showing the position of certain elements of the latter at a different stage in the operation of the machine; and

Fig. 3 is a vertical sectional view taken on the line 33' of Fig. 1 through the gear box of the machine.

As above indicated, the present invention relates only to certain improvements and additions in and to the mechanism disclosed in my copending application Serial No. 112,659, now Patent No; 2,633,219, and it is accordingly unnecessary here to repeat the detailed description of the basic mechanism.

The knife bar (not shown) is adapted to be reciprocated by reciprocation of connecting rod I pivotally connected to a crank 2 keyed to the end of a crankshaft 3 journall'ed in gear box or housing 4 within the base of the paper cutting machine. Such crankshaft is driven by gear 5 keyed thereto in turn driven by worm gear 3 keyed on shaft i. Drive shaft '1 is journalled at one end in housing 4 and at the other end in a bearing 5 supported by the upstanding end portion of main frame member 9. Flywheel ill and pulley I are freely rotatably mounted on shaft 7 for rotation together, so that such fiy- Wheel may be driven in conventional manner through such pulley and belt means from an electric motor (not shown).

A disc clutch l2 of well-known construction is provided adapted releasably to engage flywheel ltl in driving relationship to drive shaft 1, such action being effected by shifting of cone 3 E3 to the right as viewed in 1 to spread clutch actuating fingers M. The disc-type brake I is operative to stop rotation of shaft 1 when actuated by shifting of cone It to the left as viewed in Fig. 1 to spread brake actuatin fingers It will be understood that the two cones l3 and |B are joined by a sleeve H; of less diameter forming a peripheral groove in which are engaged the shifting hoe of yoke I9. Such yoke is keyed to clutch operating shaft 2c so that when such latter shaft is rocked to rock yoke Hi to the left as viewed in Fig. 1 the flywheel ID will be disengaged and brake l5 engaged, and when rocked to the right the flywheel will be engaged in driving connection with shaft l and brake |5 will be disengaged. A hand operating lever (not shown) will also be keyed to shaft 29 thus manually to rock the same.

A collar 2| is freely rotatably mounted on the end of crankshaft 3 and provided with a radially outwardly extending abutment 22 for a purpose explained below. A brake operating lever 23 is pivotally eccentrically connected to such collar 2| at 24 by means of a longitudinally adjustable link 25. A lost motion connection between such link and lever 23 is afforded by means of a slot 25 in the end of such link in which stud 21 on the end of lever 23 is slidably engaged.

A dog 28 is keyed to crankshaft 3 for rotation therewith and is adapted to engage face 29 of abutment 22 on collar 2| to carry such latter collar with it as such shaft rotates in a counterclockwise direction as viewed in Figs. 1 and 2.

The general operation of the above-described mechanism is as follows. After a stack of sheets has been properly positioned on the table of the paper cutting machine against the back gauge, the operator first moves the usual clutch lever to rock shaft 20 in a counterclockwise direction as viewed in Fig. 1. Such movement of the clutch lever may also be utilized to initiate downward movement of the conventional binder clamp to clamp the stack of sheets on the table prior to making the cut. While, as shown in Fig. 1, the brake I5 is already on, it will be apparent that cone l6 may still be shifted slightly more to the left with very little additional spreading of brake actuating fingers ll. Such rocking of shaft 20 in a counterclockwise direction simultaneously rocks lever 23 slightly toward crankshaft 3 to allow link 25 sufficient play so that eccentric connection 24 of such link with collar 2| may drop down past the center line of crankshaft 3. The crankshaft, of course, with dog 23 keyed thereto does not turn at this stage in the proceedings, so dog 28 will have been left behind and no longer is in engagement with face 29 of abutment 22. It is now possible to rock shaft 20 in a clockwise direction to shift cones l5 and I3 to disengage the brake and engage the flywheel, thereby causing crankshaft 3 to be driven through gears 6 and 5 to reciprocate the knife bar connecting rod to make the cut. As crankshaft 3 turns, dog 28 is again brought into engagement with face 29 of abutment 22, thereby rotating collar 2| therewith and carrying pivotal connection 24 of link 25 around in a counterclockwise direction from the Fig. 2 position to the Fig. 1 position.

When crankshaft 3 has revolved sufliciently (one complete revolution) to return crank 2 to its Fig. 3 position (thereby likewise again elevating the knife to its uppermost position), dog 28 bearing against abutment 22 will have rotated collar 2| to draw link 25 into engagement with stud 2'! on brake operating lever 23. Such latter lever will as a result have been rocked in a counterclockwise direction into Fig. 1 position, thereby likewise rocking yoke !9 to disengage flywheel l0 and apply brake l5. The length of link 25 is, of course, adjusted to ensure that lever 23 will have been rocked sufficiently positively to apply brake IE to stop shaft 1 before the center line of such link passes the center line of crankshaft 3. In other words, any final tendency of crankshaft 3 to continue rotation once the mechanism has reached the Fig. 1 position merely serves through engagement of dog 28 with abutment 22 to draw link 25 tighter and apply brake l5 more firmly. Knife 1 is accordingly prevented from repeating the cut or indeed even passing the uppermost point in its reciprocation.

Dog 28 is, of course, keyed to shaft I in proper position relative to crank 2 so that such dog will cause link 25 to be pulled to apply the brake when the crank has returned the knife to uppermost or rest position. The gearing 5 and 6 may be of the irreversible type although this is not necessary. When the machine has been stopped by brake Hi, there is in any case insufiicient leverage applicable on eccentric 24 to permit the operator to rock shaft 20 to disengage brake |5 without first rocking such shaft further to apply the brake and at the same time to permit the pivotal connection 24 to drop past dead center, since this would otherwise require reverse rotation of crankshaft 3. While in the specific mechanism described by way of illustration of my invention I have shown the elements so arranged and adjusted that eccentric connection 24 will drop past dead center under the influence of gravity when lever 23 is rocked theretoward, it is, of course, obvious that a spring may be provided to supplement or replace rellance on gravity for this purpose.

The above-described mechanism is disclosed and claimed in my co-pending application Serial No. 112,659. As shown in Figs. 1 and 2 of the drawing, I now additionally provide supplemental positive stop means as a safety precaution in the event the above-described brake applying mechanism should fail to halt rotation of crankshaft 3 for any reason such as, for example, improper set-up of the machine or excessive wear of the brake itself. A slightly curved lever arm 30 is keyed to a short rock shaft 3| and provided with a generally horizontally extending weighted stop arm 32 cast integrally therewith. When crankshaft 3 is turning during the making of a cut, the outer end of lever arm 30 is adapted to rest against the outer periphery of the member carrying dog 28 (Fig. 2). As such dog turns, the gently inclined cam surface 33 of such dog carrying member is operative to engage and rock lever arm 30 in a clockwise direction to bring the same to the Fig. 1 position. When lever 30 reaches such position, it is secured by a latch 34 pivotally mounted at 35 adapted to engage a stud 36 on the lever 30, stop arm 32 unit. Latch 34 is urged toward rock shaft 3| by compression spring 31 encircling rod 38 and engaging bearing 39 in which rod 38 is mounted for reciprocation. Such bearing 39 is mounted for oscillation about a horizontal axis normal to rod 38 at the end of arm 40 keyed to rock shaft 20.

When lever arm 30 has been rocked into Fig. 1 position as above explained, the end 4| of weighted stop arm 32 will thereby have been elevated into position to be engaged by the face 42 of abutment 22., should. such abutment be driven. thus far through dog 26 keyed-to. thecrankshaft.

It. will: now: be seen that, when shaft 20. is rocked. at starting. position (Fig. 1) to shiftv cone- We to the left further to' apply the brake. and simultaneously to. permit eccentric connection. 24: todrop past the center line of crankshaft 3; lever arm 40 willz likewise betrockediin a counterclockwise direction pulling.- on rod 38 to disengage latch 34: and. thereby permit stop arm 32 to drop. into Fig. 2 position. Abutment 22 carrying the eccentric. pivotal connection 24 of link 25 is thereby permitted to drop down into Fig. 2 position without obstruction, and the operator may now cause shaft 20 to be rocked in a clockwise direction to engage the flywheel and disengage the brake.

Crankshaft 3' now begins to turn to reciprocate connecting rod l and thereby the knife, and dog 28' keyed to the crankshaft soon picks up abutment 22 causing. collar 2! to rotate therewith. As the crankshaft continues to turn, and after abutment 22 ha been carried around out of position to obstruct stop arm 32, the cam surface 33 of such dog engages lever arm 30 to rock stop arm 32 upwardly into position where it may engage the leading face 42 of abutment 22, and latch 34' is rocked to the left to hold stop arm 32 in such position since arm has also been rocked in a clockwise direction at the time the brake was disengaged. When crankshaft 3 has made a complete revolution back to the Fig; 1 position, the brake is again applied as above described so' that face 42 of abutment 22 is brought not quite intoengagement with the end face 4| of" stop arm 32. If for any reason, however, the brake mechanism should fail to operate properly and the crankshaft should continue to turn past this point, face 42' of abutment 22 would be brought into engagement with end face 4|. of stop arm 32 which would effectively and positively stop any further rotation. It may be noted that the axis of rock shaft 31' is, positioned so that the shock incurred under such circumstance will be directly along the length of arm 32.

In view of the foregoing, it will. be seen that I have provided not only a positive safety stop which entirely eliminates any possibility of repetition of the cycle of the paper cutting machine but also that such stop means is so interconnected with my preferred brake operating mechanism that it is automatically dropped out.

of interfering position when such brake operating mechanism is functioning properly. Accordingly, the additional safety thereby achieved is not at the expense of the smooth automatic operation of the machine.

My new safety stop means and particularly the combination of such stop with my new automatic brake control means is well suited for employment with a variety of machines such as forging machines and'presses, for example, where it may be desired automatically to stop the machine upon completion of acycle.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In. drive means for power operated machines:

of the type in which a crank isemployed tore-- ci'procate a. work-engaging. instrument, such. as

paper cutting machines, forging machines, and i the: like; the combination of. a. crankshaft to which. such crank: is secured" for rotation: therewith, a drive shaft disposed. at right. angles to said: crankshaft, gear means connecting said. crankshaft and: drive shaft for driving the'former by'the latter, a brake onsaid: drive shaft, a. flywheel. mounted? for rotation on said drive shaft spaced: from: said brake, a. clutch adapted to engagesaid. flywheel for rotationv with said drive shaft, a: rock shaft disposed: at right angles to said driveshaftarocker arm on said rock shaftoperativeiwhen rocked in one direction toward said. crankshaft to engage said brake and disengage said clutch and when rocked in the opposite. direction to releasesaid brake and engage said flywheel in driving engagement with said drive shaft, a lever secured to said rock shaft, an eccentric freely rotatably mounted on said crankshaft, a linkpivotally connecting said eccentric and said lever, said link including provision for lost motion in its pivotal connection with said lever permitting rocking of said lever toward saidcrankshaft without opposition of said link, a dog on said crankshaft adapted to engage said eccentric for rotation therewith, said link being effective, when the-pivotal connection of said link and eccentric has been thus carried around said crankshaft to a point nearly but not quite diametricallyopposite the pivotal connection of said link and lever, automatically to rock said lever to rock said rocker arm to apply said brake and disengage said flywheel, further operation being thereby prevented until said leveris manually further" rocked in the same direction to apply said brake still more firmly and incidentally' thereto topermit such pivotal connection of link and eccentric to pass such diametrically opposite point, whereupon the operating cycle may now be initiated at will by rocking said rocker arm in theopposite direction to disengage said brake and. re-en'gage said flywheel, and safety stop means automatically operative positivelyto' stop rotation of said crankshaft in the event of failure of said brake to do so, said safety stop means comprising a stop arm pivotally mounted to swing upwardly into the path of'said eccentric and todrop down out of interfering position relative to said eccentric, such pivotal mounting for said stop armv being disposed in general alignment with the direction of movement. of. said. eccentric a the latter engages the end of said stop arm to receive'the shock of impact generally" longitudinally of said stoparm, a lever arm unitary with: said stop arm and: extending: upwardly therefrom adapted to engage: the radially outer surface of said eccentric and? dog thereby to rock said top arm upwardly into the path of said eccentric to oppose the latter, latch mea-ns automatically op-- erative to retain said stop arm in such elevated eccentric opposing position, when said eccentric and dog have passed. said latter lever arm through continued rotation of said crank" shaft, the end of. said. stop arm normally being, slightly spaced from said eccentric when the. latter is brought to a halt by application ofsaid brake,. another lever keyedon saidrock shaft, and mean connecting said latter lever to said. latch adapted. to release said latch to cause said stop arm to. drop when said. rock shaft is manually rocked still more firmly to apply said brake prior to thereafter rocking said rock shaft in the other direction to release said brake.

2. In single-cycle drive means for power operated machines having a crankshaft, a brake operative to stop such crankshaft, power means operative to drive such crankshaft, and means operable to apply such brake and disconnect such power means and alternatively to release such brake and connect such power means in driving relationship with such crankshaft; the combination of automatic control means comprising a lever adapted when rocked in opposite directions thus to regulate such alternative application of brake and power, an eccentric having a generally radially extending forward face, having regard to the normal direction of rotation of said eccentric, means connecting said lever and eccentric adapted to rock said lever to apply said brake and disconnect said power means as said eccentric turns, means automatically operative during each revolution of such crankshaft to turn said eccentric with such crankshaft for a portion only of such revolution, said connecting means being effective to rock said lever sufficiently to apply said brake and disconnect said power means before passing the center of rotation of said eccentric, whereupon a, new cycle may be initiated only after first further rocking said lever in the same direction sufiiciently to permit said eccentric to rotate further to cause said connecting means to pass the center of rotation thereof, and safety stop means automatically operative positively to stop rotation of such crankshaft in the event of failure of such brake to do so, said safety stop means comprising a stop arm pivotally mounted to swing upwardly into the path of said eccentric and to drop down out of interfering position relative to said eccentric, such pivotal mounting for said stop arm being disposed in general alignment with the direction of movement of such forward face of said eccentric as such face engages the end of said stop arm to receive the shock of impact generally longitudinally of said stop arm, cam means adapted to rock said stop arm upwardly into eccentric-opposing position as such crankshaft and said eccentric thus turn together, latch means automatically operative to retain said stop arm in such elevated position during continued rotation of such crankshaft, the end of said stop arm normally being thus held slightly spaced from such forward face of said eccentric when the latter is brought to a halt by application of such brake, a second lever rockable with said first lever but extending in the opposite direction for rocking movement opposite to said first lever, and means interconnecting said second lever and latch means adapted to disengage the latter from said stop arm to permit said stop arm to drop when said first lever is rocked to permit said eccentric to rotate to cause said means connecting said eccentric and first lever to pass the center of rotation of said eccentric.

3. In a power operated machine having a rotatable element and a brake operative to stop the same; means operative automatically to apply such brake comprising an eccentric adapted to be driven together with said element but at all times free to turn in advance thereof, control means for such brake pivotally connected to said eccentric and adapted to be reciprocated thereby to apply such brake before the point of pivotal connection passes dead center of said eccentric, whereupon a new cycle of operation may be initiated only after first moving such point of pivotal connection beyond dead center, and safety stop means automatically operative positively to stop rotation of said eccentric and therefore of such element in event of failure of such brake to do so, said safety stop means comprising a projection on said eccentric disposed radially outwardly from the center of rotation thereof, a stop member pivotally mounted for swinging movement into and out of position to engage said projection to oppose further rotation of said eccentric, such pivotal mounting for said stop member being disposed in general alignment with the direction of movement of said projection as the latter approaches said stop member to support the shock of impact therebetween, cam means adapted to rock said stop member into projection-opposing position as said eccentric rotates with said element, latch means automatically operative to retain said stop member in such projection-opposing position during continued rotation of said element and eccentric together, said stop member being adapted normally to assume non-projection-opposing position, said control means being normally operative to apply such brake to halt rotation of said element and eccentrio with said projection spaced from said stop member, and means operative simultaneously to release said latch means and to move such point of pivotal connection of said control means and eccentric beyond dead center.

4. In a power driven paper cutting machine having, a crankshaft adapted when rotated to reciprocate a knife, a brake for such crankshaft, a flywheel adapted to drive such crankshaft, and a clutch operative to engage such flywheel in and disengage such flywheel from driving relationship with such crankshaft; means operative automatically to apply such brake and disengage such flywheel after completion of one cycle of such machine comprising a freely rotatably mounted eccentric, means on such crankshaft adapted to engage said eccentric for rotation therewith, a lever operative when rocked in one direction to engage such brake and operate such clutch to disengage such flywheel and when rocked in the opposite direction to release such brake and operate such clutch to engage such flywheel, a link pivotally connecting said lever and eccentric having a length effective to rock said lever to apply such brake and disengage such flywheel shortly before the point of pivotal connection of said link and eccentric reaches dead center relative to said eccentric, whereupon a new cycle may be initiated only after first further rocking said lever in the same direction sufiiciently to permit such connection of link and lever to pass dead center, and safety stop means automatically operative positively to stop rotation of said eccentric and therefore such crankshaft in the event of failure of such brake so to do, said safety stop means comprising a stop member pivotally mounted for swinging movement into and out of position rigidly to oppose rotation of said eccentric, a projection on said eccentric adapted to engage said stop member to halt further rotation of said eccentric, said stop member being adapted normally to assume its non-eccentric-opposing position, means operative automatically to swing said stop member into eccentric-opposing position during rotation of such crankshaft and eccentric, said brakeapplying means being normally operative to apply such brake to halt rotation of such crankshaft and said eccentric before said projection is brought into engagement with said stop member, and means adapted to be actuated by such fur- 9 ther rocking of said lever operative to release said stop member for return to its normal noneccentric-opposing position to permit further rotation of said eccentric.

5. In a power driven paper cutting machine having, a crankshaft adapted when rotated to reciprocate a knife, a brake for such crankshaft, a flywheel adapted to drive such crankshaft, and a clutch operative to engage such flywheel in and disengage such flywheel from driving relationship with such crankshaft; means operative automatically to apply such brake and disengage such flywheel after completion of one cycle of such machine comprising a freely rotatably mounted eccentric, means on such crankshaft adapted to engage said eccentric for rotation therewith, a lever operative when rocked in one direction to engage such brake and operate such clutch to disengage such flywheel and when rocked in the opposite direction to release such brake and operate such clutch to engage such flywheel, a link pivotally connecting said lever and eccentric having a length effective to rock said lever to apply such brake and disengage such flywheel shortly before the point of pivotal connection of said link and eccentric reaches dead center relative to said eccentric, whereupon a new cycle may be initiated only after first further rocking said lever in the same direction Sllfilciently to permit such connection of link and lever to pass dead center, and safety stop means automatically operative positively to stop rotation of said eccentric and therefore such crankshaft in the event of failure of such brake so to do, said safety stop means comprising a stop member mounted for shifting into and out of position rigidly to oppose rotation of said eccentric substantially beyond the normal stopping position of the latter upon such automatic operation of such brake, means automatically operative to shift said stop member into such eccentric-opposing position during rotation of such crankshaft and eccentric, and means adapted to be actuated by such further rocking of said lever operative to shift said stop member out of such eccentric-opposing position to permit further rotation of the latter.

6. In a power driven paper cutting machine having, a crankshaft adapted when rotated to reciprocate a knife, a brake for such crankshaft, a flywheel adapted to drive such crankshaft, and a clutch operative to engage such flywheel in and disengage such flywheel from driving relationship with such crankshaft; means operative automatically to apply such brake and disengage such flywheel after completion of one cycle of such machine, and safety stop means automatically operative positively to stop rotation of such crankshaft in the event of failure of such brake so to do, said safety stop means comprising a rotatable member driven by such crankshaft, a stop member mounted for shifting into and out of position rigidly to oppose rotation of said rotatable member substantially beyond the normal stopping position resulting from such automatic operation of such brake, means actuated by rotation of such crankshaft operative to shift said stop member into such opposing position, and manually operable brake-applying means adapted when thus operated also to return said stop member out of position opposing further rotation of said rotatable member and such crankshaft.

7. In mechanism including a rotatable element such as a crankshaft, drive means therefor, and brake means normally automatically operative to stop rotation of said element upon completion of a cycle; safety stop means automatically operative positively to stop rotation of such element in the event of failure of such brake means so to do, said safety stop means comprising a stop member mounted for shifting into and out of position rigidly to oppose further rotation of such element substantially beyond the normal stopping position resulting from such automatic operation of such brake, means operative in timed relation to rotation of such element thus to shift said stop member into rotation-opposing position, manually operable brake-applying means adapted when thus manually operated further to apply such brake more forcefully than such automatic application thereof, and means actuated by said manual brake-applying means operative to return said stop member out of position to oppose further rotation of such element.

8. In mechanism including a rotatable element such as a crankshaft, drive means therefor, and brake means normally automatically operative to stop rotation of such element upon completion of a predetermined cycle; safety stop means automatically operative positively to stop such rotation in the event of failure of such brake means so to do, said safety stop means comprising a stop member movable into and out of position to oppose further rotation of such element substantially beyond the normal stopping position of the latter under influence of such brake means, means automatically operative in timed relation to rotation of such element thus to shift said stop member into rotation-opposing position, and manually operable control means adapted, when shifted in one direction, both further to apply such brake and simultaneously, by such shifting, to return said stop member out of position to oppose further rotation of such element and, when subsequently shifted in another direction, to release such brake to permit further rotation of such element by such drive means.

9. In mechanism including a rotatable element such as a crankshaft, drive means therefor, and brake means normally operative to stop rotation of such element upon completion of a predetermined cycle; safety stop means automatically operative positively to stop such rotation in the event of failure of such brake so to do, said safety stop means comprising a stop member pivotally mounted for swinging movement about an axis parallel to the axis of rotation of such element, a generally radial face on such rotatable element adapted to engage said stop member in one position of the latter, such pivotal mounting for said stop member being disposed in general alignment with the direction of movement of said face when said face thus engages said stop member, thereby rigidly to support the shock of impact directly toward such pivotal mounting, and means operative to swing said stop member into and out of face-engaging position.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 443,398 Malm Dec. 23, 1890 728,269 Mills May 19, 1903 1,036,975 Dexter et al Aug. 27, 1912 1,105,695 Reiman Aug. 4, 1914 

